Braxton Hicks or baby?

Brooke
Several times a day, I feel an intense tightening sensation in my lower stomach, feeling almost exactly like a BH, but when I feel my uterus it's only hard on one side. Do you think it's a BH, or is it the baby already bunching up on one side of my belly? I'll be 17 weeks tomorrow and this is my third pregnancy, but I feel like it's too early for either of these.